- seCtIon FIVe: BoRDeRLAnDs
DEFINING ASCS
James’s ‘other forms of consciousness’ would now be called ‘altered states of con-
sciousness’ or ASCs – a concept that seems simple but is notoriously difficult to
define. I get drunk and so feel and act differently; I recover from depression and
wonder how life could ever have felt so unliveable; I feel like a calmer person on
the meditation mat. In all these cases, something has obviously changed, but
what? As soon as we start to think more deeply about altered states of conscious-
ness, the problems begin.Should we define ASCs objectively or subjectively? Taking objective defi-
nitions first, we might define ASCs in terms of how they were induced, for
example by mind-altering drugs or by hypnosis or progressive relaxation.
Then we might label different drug-induced states according to which drug
the person took, saying that someone was drunk on alcohol, stoned on can-
nabis, tripping on LSD, or spaced-out or loved-up on ecstasy. But numerous
problems make this unsatisfactory. How do we know whether your trip is
similar to mine? How do we know whether two slightly different drugs pro-
duce the same, or different, ASCs? And how can we measure the similarity so
as to make such decisions? Then there is dosage. How much cannabis does
someone need to take to say that they have reached the stoned ASC? Even
if two people do experience similar states, the dose required may be quite
different for each person. We might define a hypnotic state in terms of a par-
ticular hypnotic procedure, but that same procedure might have no effect on
someone else. Defining and categorising ASCs by the way they are induced
is not satisfactory.Perhaps a better solution is to define ASCs on the basis of physiological and
behavioural measurements, such as heart rate, cortical oxygen consumption,
ability to walk in a straight line, or expressions of emotion. One problem here
is that very few ASCs are associated with unique physiological patterns (a
partial exception is sleep, Chapter 15) or with physiological or behavioural
changes that map directly onto changes in experience. As methods improve,
we may find consistent patterns, enabling us to define the states in terms of
those measures. But it may turn out that very small changes in physiology can
be associated with large changes in subjective state, and vice versa, so that
no direct mapping is possible. For the moment, we should be careful about
defining a state of consciousness (SoC) in terms of physiology. There is a dan-
ger of losing the very essence of ASCs, which is how they feel for the person
concerned.
The alternative is to define ASCs subjectively, and although objective definitions
are sometimes used (e.g. Revonsuo et al., 2009), this is the most common strat-
egy. The term ASC was first formally defined by American psychologist Charles
Tart as ‘a qualitative alteration in the overall pattern of mental functioning, such
that the experiencer feels his consciousness is radically different from the way
it functions ordinarily’ (1972a, p. 1203). An early textbook on consciousness
described the ASC as ‘a temporary change in the overall pattern of subjective
experience, such that the individual believes that his or her mental functioning
is distinctly different from certain general norms for his or her normal waking